Q: I have a question for you. Is it always raining in some part of the world every day? – Olivia, age 10, Rocklin
A: Olivia’s question was answered by National Weather Service meteorologist Brent MacAloney, who writes:
Yes. Thanks to the Earth’s water cycle, it is always raining in some part of the world every day. Rain is a form of precipitation, much like snow. As the precipitation falls from the atmosphere, the Earth collects it in soil, plants and bodies of water. As the sun heats the Earth, a portion of this precipitation will evaporate or transpire into the form of water vapor. The water vapor will then rise from the ground into the atmosphere, where it will condense due to cooler temperatures.
This condensation process will turn the water vapor into small cloud droplets. As additional amounts of water vapor condense, the cloud droplets will combine with each other until the point at which they can no longer be supported in the atmosphere. At this point, it begins to rain or precipitate, thus beginning the whole water cycle process again. This water cycle is constantly working in the Earth’s atmosphere, all over the world. So at any given point, it is raining somewhere on the Earth due to the water cycle.